低银活性钎料钎接95% Al_2O_3陶瓷与可伐合金4J33的研究

Brazing of 95% Al_2O_3 ceramic and kovar 4J33 with lower-Ag activity fillers

针对预金属化法钎接陶瓷与金属工艺复杂以及钎料含银量高问题,设计制备出AgCuSnInTiNi活性钎料箔,并用之对95%Al_2O_3陶瓷与可伐合金4J33实施真空钎接,分析了接头组织和性能,研究了钎料中钛含量对接头组织和性能的影响。结果表明,随着钛含量的增加,钎料熔点升高,铺展性明显改善,AgCuSnInTiNi钎料可实现95%Al_2O_3陶瓷与可伐合金4J33的有效连接,形成的钎接接头饱满,无裂纹、溶蚀等缺陷。钎缝组织均匀致密,主要由(Ag),(Cu)及分布于晶界的Cu_2Ti,AgTi化合物组成。由于钎接过程中合金中的Fe,Ni元素溶解,在钎缝与可伐合金的结合界面有少量Fe_2Ti,Ni_3Ti脆性化合物产生。在钎缝与陶瓷的结合界面存在厚约10μm的Ti_3Cu_3O,TiO,TiAl_3反应层,达成陶瓷与钎缝的连接。随着Ti含量增加,钎料与母材反应充分,钎缝组织细化,成分均匀,接头剪切强度增大。但当钛含量大于6%时,接头化合物增多,性能有下降趋势。在钎接温度870℃、保温时间5min、真空度为2.0×10-2Pa条件下,应用Ag42Cu45.8Sn4In2Ti6Ni0.2钎料钎接95%Al_2O_3陶瓷与可伐合金4J33,形成接头的剪切强度达到107MPa。

The traditional metallization brazing method of ceramic to metal has the problems of complicated process and filler with high silver content. AgC uS nI nT iN i filler foil was designed by rapid cooling to braze 95% Al_2O_3 ceramic to 4J33 Kovar alloy in vacuum,the interface microstructure,property,and the effect of different content of Ti on the microstructure and performance of the joint were analyzed. The results indicate that the melting-point grows and the wettability on ceramic improve as the content of Ti increasing. the filler foil can well braze 95% Al_2O_3 ceramic and 4J33 Kovar,a full and even joint with no cracks and corrosion can be obtained. The brazing seam center is mainly composed of( Ag) and( Cu); and continuous dot compounds of Cu_2Ti and AgTi formed in the grain boundary. In the brazing process,Fe and Ni elements in Kovar alloy diffuse into filler alloy,which results in the formation of some brittle compounds of Fe_2Ti,Ni_3Ti in the interface of alloy and filler metal. In the interface of ceramic and filler,a reaction layer of Ti_3Cu_3O,TiO,TiAl_3 about 10 μm in thickness forms,which achieves the joining of brazing ceramic to Kovar. As the content of Ti increasing,the filler and the base metal react more fully,fine brazed seam microstructures refine,uniform compositions,and hihg shear strength of joint can be achived. While it is more than 6%,the compounds increase and the properties decrease. At brazing temperature of 870 ℃,holding time of 5 min and vacuum degree of 2. 0 × 10^(-2)Pa,the 95%Al_2O_3ceramic and 4J33 Kovar were brazed with Ag42Cu45. 8Sn4In2Ti6Ni0. 2 filler,and the shear strength of the joint is 107 MPa.